RFR: Add a limition to allocate object heap in aarch64 with tsan enabled.

[Jie He]

On Tue, 21 Apr 2020 08:16:38 GMT, Jie He <github.com+10233373+jhe33 at openjdk.org> wrote:

>> yes, I think it's possible, however it will touch X86 code that moving has_allocatable_memory_limit() to
>> os_linux_x86.cpp as well.
>
> I will move it and test x86. thank you for reminding.

@caoman I think it's better to put the code into os_posix.cpp with TSAN_ONLY, AARCH64_ONLY, not os_linux_aarch64.cpp,
because latter has to make multiple copies of function has_allocatable_memory_limit for archtectures. And in
os_linux.cpp, AARCH64, X86_64 specific code is allowed. what do you think?

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PR: https://git.openjdk.java.net/tsan/pull/6